One of the main problems in a complex and signal-rich environment is to ascertain the precise origin of any given signal. If we define origin by its physical location then this identification is not problematic as long as there are definite communication channels, say between a signal emitter and a receiver. The wide area network of the Internet or World Wide Web, with its packet-switching protocols, is an example of such a complex but resolved situation.
But even if the physical location or the positive identification of an emitter can be recorded, this does not ensure a well-defined origin when we define origin by the source of the data stream itself.
Numerous situations exist where a measuring system or any system can be fooled about the precise nature or origin of said measurements. Situations like spoofing, phishing, . . . unreliable online identities, all the various strategies to hide the identity of the data, including data forgery or any misleading intent or accidental interference are just a few examples of a near un-limited list of possibilities. The more we are moving towards mobile devices (the web of things, mobile apps for health, remote monitoring, online banking, . . . ), the more likely the risk of having corrupted or non-properly authenticated data.
For years, companies have tried to establish an identity system for users of the Internet or World Wide Web. The basic premise being that users should have a single trusted identity, the incentive for such idea being that it could ease all user interactions offline and online. Microsoft proposed Passport in the late 1990s, but privacy concerns and the FTC made it difficult. Facebook's social graph is another effort. Google+ is another. Google+ is not as much a social site as an ‘identity service’. Before Google+, your Google identity was really only used on Google sites. But with Google+ and the +1 button, the identity system can extend across the Internet or World Wide Web. When a user is signed into the Google+ system, his/her information can be tracked. The tracked information helps Google provide more personalized services (like search results) to a user, and also helps with ad targeting to the user.
For secure communication, the banking industry often relied on either secure communication links or complex codes embedded (or not) in the transaction data themselves. Most systems still rely on various levels of keys and/or encryption.
However, problems associated with accidental miss-identification or voluntary/involuntary identity swaps remain. As examples, a bank card or a PIN may be stolen; one may lie; a person's identity may be stolen.